Can maize variety influence the mineralisation of soil organic matter and supplement inorganic fertilisers for nitrogen supply in soil?

Plant species and genotypes vary with respect to the degree to which they mediate soil organic matter mineralisation. For example, as a consequence of rhizodeposition amount and composition shaping rhizosphere microbial community structure and increasing microbial activities, including mineralisation of soil organic matter. A consequence of soil organic matter mineralisation is the mobilisation of ammonium and subsequent nitrification, both providing N available for plant uptake. Therefore, there is the potential for manipulating this root-soil interaction through breeding to help meet soil nitrogen supply in cropping systems, especially in low input systems of tropical and subtropical areas.

As part of the project “Exploiting the potential of genotype microbiome interactions to promote sustainable soil health in southern Africa”, the University of Edinburgh and partners explored maize genotype-specific influences on soil organic matter mineralisation and gross nitrification under conventional management versus no-tillage with crop residue retention. Using microcosm experiments, root traits linked to enhanced soil organic matter mineralisation and gross nitrification were revealed. Candidate genes related most closely to these root traits have been identified. These results and implications for breeding, soil organic matter/nutrient management and sustainable production will be shared in this presentation.

Co-researchers: Prof Liz Baggs, University of Edinburgh, UK; Dr Eric Paterson, The James Hutton Institute, UK; Prof Tim Daniell, University of Sheffield, UK; Dr Jill Cairns, CIMMYT, Zimbabwe; Dr Christian Thierfelder, CIMMYT, Zimbabwe; Dr Manje Gowda, CIMMYT, Kenya.